AMD's Next-Generation Mobile Architecture Revealed: Griffin
by Anand Lal Shimpi on May 18, 2007 12:10 AM EST- Posted in
- CPUs
Mobile Specific HT3
Much like Phenom, Griffin will support HyperTransport 3, offering more bandwidth between the CPU and the outside world. A major change to Griffin's HT interface however is that it is highly power optimized.
By default, a Griffin CPU has two x16 HT3.0 links (one inbound and one outbound); depending on power and bandwidth requirements, those links can be dynamically scaled down to x8, x4, x2 or completely turned off. The inbound and outbound lanes can dynamically change independent of one another (e.g. inbound could be scaled to x8 while the outbound could be turned off). Each link width change requires a HT disconnect, meaning it can't be done as frequently as a CPU frequency change, but the power savings should be substantial.
Better Thermal Control
Griffin adds better thermal control than its predecessor. The mobile K8 cores simply had a single on-die analog thermal diode that would report CPU temperature, while Griffin features two thermal sensors per core for more accurate thermal monitoring.
The current generation Turion CPUs communicate processor thermal data over the SMBUS, however an external thermal monitoring circuit is used requiring additional board real estate. Griffin supports an integrated SMBUS interface directly to the chipset, so there's no extra chip required.
Griffin also allows monitoring of DRAM temperature (through an external temperature sensor placed near the DRAM modules) and based on pre-configured thermal limits, it can now throttle memory frequency if the modules get too hot.
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yyrkoon - Friday, May 18, 2007 - link
I can not help but think 'WHY' a laptop *NEEDS* more than one core on the CPU. Anyone claiming that their laptop is comparrible to the performance of a good desktop, is only kidding themselves. From my point of view, a laptop is a tool, used to do whatever you can not do on the desktop, for whatever reason ( travelling, and away, from your desktop, etc ). Yes, I understand that multiple core CPU have been availble in laptops for some time now, but that does not really answer my question. The point I am getting at here, is that if the laptop CPU could be made aroudn a single core, there should be plenty of room for other enhancements, and a potential for a lower TDP.The statement above, to me resembles something along the lines of the difference between USB v2.0, 400Mbit firewire , and syncronous/asyncronous read/write capabilities, there *HAS* to be a performance hit here . . . Who knows, maybe I am wrong ?
Justin Case - Sunday, May 20, 2007 - link
A second core does make a very significant difference in terms of system responsiveness, even if you rarely (or never) max out both CPUs. I started using dual-CPU systems about 8 years ago and never looked back.More and more people are using a laptop as their only PC, so that theory that laptops are just typewriters isn't true anymore. They used to be just typewriters because that was all they _could_ do.
With proper power management, a dual-core CPU can consume as little as a single-core one, for the same amount of work, so the only issue becomes the price of the chip itself. And since dual-core CPUs are so cheap, these days, there's really no reason not to have one.
Eris23007 - Friday, May 18, 2007 - link
My company issued me a laptop, complete with anti-virus, software firewall, and hard disk encryption preinstalled that I can't turn off. My system runs two antivirus scans a week on the whole hard drive (at about 4 hours each). Given that an antivirus scan requires considerable hard disk access, that means that in addition to the processor load for running the virus-scanning algorithms, there's also substantial load for decryption.
Unfortunately this laptop is a single-core Pentium M - no Core 2 Duo for me. My friend who hired on a little after I did got the Core 2 Duo version. The difference is astounding. My laptop (on XP, of course) has significant usability constraints - even the UI just isn't very responsive because of all the crap running in the background.
I would *LOVE* to have an extra core around, dedicated to handling this bullcrap. It would make a tremendous difference in my ability to actually "get work done" when my system would otherwise be busy running all this junk.
I'm aware that the extra core wouldn't improve the hard disk situation - but it would DEFINITELY help a WHOLE lot.
ADDAvenger - Friday, May 18, 2007 - link
There's more people than you'd think who have a laptop as their only computer, and I am one of them. Yeah a laptop doesn't NEED dualcore, but believe me, it does make more of a difference than you want to give it credit for. I'm in college and take notes on this thing all day, a desktop just wouldn't work for me, and I just don't have the money to have both right now.Wolfpup - Friday, May 18, 2007 - link
Totally agree. I can't wait for quad core laptops. And yes, I intend to use my laptop as my only computer.sprockkets - Friday, May 18, 2007 - link
because it was demonstrated that adding another core did not make any difference in battery life while increasing performance.JackPack - Friday, May 18, 2007 - link
The new Intel Merom M0 stepping processors already supports something similar. With single threaded apps, one core goes down to C3 while the other speeds up to a turbo frequency (bin + 1) while staying below or at the specified TDP.
goku - Friday, May 18, 2007 - link
I agree with this as well. People really expect laptops to be something that can do everything and it really is unreasonable. That said, AMD and Intel are making their computers more powerful so that people can start using laptops exclusively as that is the market trend, to go away from desktop machines.I'm wondering if AMD supports completely turning off a core and having it run in single core operation as I'd think running in single core mode with a slightly higher clock speed (if at all) would be more power efficient than having two slower cores running simultaneously. No need to have two cores running when you're just typing in MS word. It'd also be nice if intel and AMD would support far slower clocks speeds as IIRC the minimum clock speed increased from 600mhz on the Dothan and Banias machines to 800mhz on newer machines.
If I could get my laptop to downclock to 100mhz when I'm typing in Word and reduce the voltage considerably, I bet you'd see a much higher jump in battery life. But with vista being so bloated today, the computer would probably never downclock to a speed as low as that since XP and vista seemingly are always busy.
CrystalBay - Friday, May 18, 2007 - link
Kinda sounds like Barcelona, is not the panacea people were hoping for...Hulk - Friday, May 18, 2007 - link
Anand pretty clearly stated that Griffen is not based on Barcelona but on K8.I'm not really getting how this strategy will help AMD in the mobile market though. The current K8 core is getting pasted by C2D today clock-for-clock. And from what I just read I don't think the improvements made to create Griffen will enable to catch up to C2D IPC-wise.
Add to that the fact that by the Griffen release time Penryn will be widely available at 45nm. More power efficient than current mobile C2D offerings, faster, and with better IPC.
Like I said, I don't get it?